SEARCH · PubMed Health

Results for “Meta- analysis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 613 records · Page 34Linked to original sources

PubMed1996

Low-dose corticosteroids in rheumatoid arthritis. A meta-analysis of their moderate-term effectiveness.

OBJECTIVE: To perform a systematic literature review and meta-analysis of the effectiveness of low-dose corticosteroids in the treatment of rheumatoid arthritis (RA). METHODS: After identifying all relevant studies meeting preselected inclusion criteria, we performed 2 meta-analyses. First, we compared the effectiveness of prednisone to placebo and active drug controls (aspirin, chloroquine, or deflazacort) using standard meta-analysis methods for continuous data. Then, to compare the relative effectiveness of prednisone to second-line agents, we used methods similar to prior meta-analyses of second-line agents for RA treatment. Outcomes assessed were the number of tender and swollen joints, grip strength, and the erythrocyte sedimentation rate (ESR). RESULTS: Very few studies directly assessed the effectiveness of corticosteroids for RA treatment, and many were of poor methodologic quality. Only 9 of 34 studies identified by our search met criteria for inclusion. The results of our standard meta-analysis indicated that corticosteroids appeared to be more effective than either placebo or active drug controls in improving most conventional outcome measures (effect size 0.90 for the number of tender joints, 1.05 for the number of swollen joints, and 1.20 for the ESR). In our second comparative meta-analysis, corticosteroids were nearly equivalent to second-line agents previously examined in meta-analyses (combined effect size 0.82). CONCLUSION: Based on the limited data available, during moderate-term treatment periods averaging slightly over 7 months, corticosteroids appeared to be as effective or more effective than alternative therapies in improving several common RA disease activity measures.

Anti-Inflammatory Agents↗

PubMed2001

A meta-analysis of rape education programs.

Meta-analysis of evaluation studies of rape education programs aimed at college students examined which program characteristics were related to participants' rape-supportive attitude change. Linear regression analyses revealed that: (a) published studies yielded greater attitude change than dissertations, presentations, or unpublished studies; (b) attitude change declined over time; and (c) men in mixed-gender groups experienced less attitude change after interventions than men in single-gender groups. Implications for the development of effective rape education programs are discussed.

Health Education↗

PubMed2006

Assessing heterogeneity in meta-analysis: Q statistic or I2 index?

In meta-analysis, the usual way of assessing whether a set of single studies is homogeneous is by means of the Q test. However, the Q test only informs meta-analysts about the presence versus the absence of heterogeneity, but it does not report on the extent of such heterogeneity. Recently, the I(2) index has been proposed to quantify the degree of heterogeneity in a meta-analysis. In this article, the performances of the Q test and the confidence interval around the I(2) index are compared by means of a Monte Carlo simulation. The results show the utility of the I(2) index as a complement to the Q test, although it has the same problems of power with a small number of studies.

Analysis of Variance↗

PubMed2026

Intraocular Pressure Changes Following Intraluminal Stent Removal From the Paul Glaucoma Implant: A Systematic Review and Meta-Analysis.

PURPOSE: This study aims to systematically review and perform a single-arm meta-analysis to comprehensively evaluate the effect of removal of intraluminal stent from the Paul glaucoma implant (PGI) on intraocular pressure (IOP) changes and to summarize its long-term efficacy and safety. CLINICAL RELEVANCE: Glaucoma remains one of the leading global causes of irreversible vision loss, necessitating effective surgical management for refractory cases. Glaucoma drainage devices are critical for these complex forms, and intraluminal stent removal from the PGI serves as a key strategy to titrate aqueous outflow and optimize long-term IOP control. METHODS: A systematic review was conducted by searching EMBASE, Medline, and CENTRAL. The meta-analysis ultimately included 5 observational studies. The Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tool was used to assess the quality of the included studies. Continuous outcomes (eg, postremoval stent IOP reduction) were analyzed using the mean difference (MD) with 95% confidence intervals (CI); dichotomous outcomes (eg, hypotony incidence) were evaluated using pooled proportion with 95% CI. All meta-analyses employed a random-effects model. RESULTS: Our meta-analysis included 5 studies, involving a total of 283 eyes. The meta-analysis revealed that removal of the stent leads to a significant and immediate IOP reduction. The IOP reduction (immediate postremoval stent IOP minus preremoval stent IOP) was significant, with a pooled MD of -9.09 mm Hg IOP (MD = 9.09; 95% CI = [-11.77, -6.41]). In the preremoval stent high-IOP (>21 mm Hg) subgroup, the IOP reduction is -11.82 (95% CI = [-10.14, -13.51]). This reduction was significantly greater than the preremoval stent low-IOP (<21 mm Hg) subgroup, whose reduction is -6.66 mm Hg (95% CI = [-5.55, -7.77]). Regarding safety, the pooled proportion of clinically hypotony was low and highly consistent (I² = 0.00%) at only 0.03 (95% CI = [0.00, 0.15]). CONCLUSIONS: Intraluminal stent removal from the PGI is an effective and safe IOP-lowering intervention. Its IOP reduction effect is significantly more pronounced in patients with preremoval stent high IOP, providing crucial clinical guidance for managing persistently high IOP after PGI implantation.

Humans↗

PubMed1992

Meta-analysis of observational epidemiological studies: a review.

Meta-analyses (integration of findings by quantitative analyses of results of individual studies) are already widely used in the psychological and educational sciences and in the pooling of clinical trial results. Examples of the application of such techniques to the results of observational epidemiological studies are now proliferating. In this paper meta-analysis of the results of observational epidemiological studies is reviewed. Uncritical adoption of techniques used in pooled analyses of clinical trial results may be inappropriate. Some alternative approaches, including meta-regression techniques, are discussed, and illustrated with reference to examples of meta-analyses of studies of breast cancer risk following oral contraceptive use and of patterns of post-bereavement mortality. Although substantial difficulties beset the use of meta-analysis in epidemiology, many of these problems are also implicit in the execution of traditional, narrative reviews. Foremost among these difficulties are those associated with publication bias and with making due allowance for the quality of the studies being combined. Unlike traditional narrative reviews, meta-analyses require explicit statement of the criteria for the review and hence highlight these difficulties. Nonetheless, careful and critical application of appropriate meta-analytical techniques facilitates quantitative exploration of inhomogeneities in, and (where appropriate) synthesis of study results.

Epidemiologic Methods↗

PubMed1996

Defined-formula diets versus steroids in the treatment of active Crohn's disease: a meta-analysis.

BACKGROUND: To compare the effectiveness of defined-formula diets versus steroids for the treatment of active Crohn's disease, we conducted a meta-analysis of the published clinical trials. METHODS: Standard techniques for literature search were used to identify the pertinent trials. All studies included in our meta-analysis (n = 7) were aimed at comparing defined-formula diets versus steroids, using a randomized design. The patient-specific end-point of the meta-analysis was the occurrence of a treatment failure. RESULTS: Our meta-analysis indicated that steroids are more effective than defined-formula diets for inducing remission in active Crohn's disease. In fact, the relative risk of treatment failure (RTF) was significantly lower in the steroid group than in the diet group (risk values for patients given steroids compared with patients given diet: a) method of Mantel-Haenszel: RTF = 0.35; 95% confidence interval, 0.23-0.53; p < 0.001; b) method of Der Simonian & Laird: RTF = 0.43; 95% confidence interval, <0-0.94; p = 0.03). A separate analysis was carried out in which only the subgroup of patients who were not intolerant to diet were evaluated; this analysis also showed a superiority of steroids over diet. CONCLUSIONS: The data examined in this meta-analysis do not support the use of diets as primary treatment for acute exacerbations of Crohn's disease in adults.

Adult↗

PubMed1999

Meta-analysis: when and how.

Systematic reviews have a central role in evidence-based medicine. The quantitative systematic review, also known as meta-analysis, provides a logical structure for quantifying evidence and for exploring bias and diversity in research systematically. It is essential that clinicians, educators, and researchers understand the methods that comprise this research tool, particularly the basic step-by-step process, and know when numerical pooling of data is appropriate. The essay describes how systematic reviews are best conducted and when statistical pooling of data is appropriate. Systematic reviews are scientific investigations with planned methods that use original studies as subjects and synthesize the results of multiple studies using strategies to limit bias and random error. This process requires judgments to be made explicit, and should be question driven, protocol based, reproducible, and comprehensive in scope. Meta-analysis provides a framework for research synthesis, increases power and precision, provides an overall estimate and range of effect, and identifies greater-than-expected variability among study results (heterogeneity). Meta-analysis does not remove subjectivity from the process of synthesis, identify sources of variability among studies, or obviate the need for sound, compassionate clinical reasoning. Statistical heterogeneity should be anticipated and welcomed. It forces a consideration of clinical heterogeneity as well as variation in study protocol and quality. Statistical tests for homogeneity are insensitive and do not indicate sources of heterogeneity, making such consideration imperative. The most common and popular measures of efficacy for a meta-analysis are the standardized difference between two means, the relative risk, and the odds ratio. An additional measure, the number needed to treat, with its 95% confidence interval is the most clinically useful measure of the effects of an intervention and is useful for comparing the relative effectiveness of different interventions for the same condition. Important parts of meta-analysis and sensitivity and subgroup analyses are best considered a priori and should be used to explore heterogeneity and to test for publication bias and variation in study quality.

Evidence-Based Medicine↗

PubMed1994

[Meta-analysis of clinical trials: values and limitations].

Meta-analysis produces reproductible, qualitative as well as quantitative overviews of available evidence. Such a synthesis is a compulsory step in conveying information on therapeutics to health care providers. Compared to more traditional approaches, meta-analysis has enough advantages to make them no longer relevant. Its limitations come from inappropriate use or less than required rigorous application of its methodology.

Clinical Trials as Topic↗

PubMed1999

Exploring heterogeneity in meta-analysis: is the L'Abbé plot useful?

By using a published meta-analysis as an example, this paper discusses the use of L'Abbe plot for investigating the potential sources of heterogeneity in meta-analysis. As compared with other graphic procedures, the L'Abbe plot is useful to identify not only the studies having different results from other studies, but also the study arms that are responsible for such differences. This may be important for determining the focus of heterogeneity investigations. Results of stochastic simulation indicate that, purely because of random variation, studies with event rates of around 50% are more likely to be identified as outliers in a L'Abbe plot. This paper also demonstrates that different methods may identify different trials as "outliers" in meta-analysis.

Computer Simulation↗

PubMed1995

Multiple-outcomes meta-analysis of treatments for periodontal disease.

The results of periodontal therapy vary by disease severity, outcome measure, and method of data analysis. Several clinical trials and a subsequent meta-analysis have demonstrated that, for teeth with severe disease, surgery decreases probing depth (PD) and increases attachment level (AL) more than non-surgical treatment. For other disease levels, the choice of therapy depends on the outcome measure. When clinical trials use two or more outcome measures (such as PD and AL), investigators ordinarily analyze each outcome separately. When the correlations are incorporated among the outcomes, a meta-analysis can use generalized-least-squares (GLS) regression to analyze multiple outcomes jointly. We applied the GLS multiple-outcomes model in a meta-analysis of 5 trials comparing surgical and non-surgical periodontal treatments, each assessing the outcomes PD and AL one year after treatment. The clinical conclusions are similar to those reported earlier, but our estimates of the relative benefits of surgical and non-surgical treatment should be more accurate, because the GLS method takes into account correlation between AL and PD. When correlations between the two outcomes rise, as they do with increasing severity of disease, the GLS estimates depart from those derived from separate analyses of PD and AL.

Dental Scaling↗

PubMed2004

Neuroimaging studies of shifting attention: a meta-analysis.

This paper reports a meta-analysis of neuroimaging studies of attention shifting and executive processes in working memory. We analyzed peak activation coordinates from 31 fMRI and PET studies of five types of shifting using kernel-based methods [NeuroImage 19 (2003) 513]. Analyses collapsing across different types of shifting gave more consistent results overall than analysis within individual types, suggesting a commonality across types of shifting. These areas shared substantial, significant overlap with regions derived from kernel-based analyses of reported peaks for executive processes in working memory (WM). The results suggest that there is a common set of brain regions active in diverse executive control operations, including medial prefrontal, superior and inferior parietal, medial parietal, and premotor cortices. However, within several of these regions, different types of switching produced spatially discriminable activation foci. Precise locations of meta analysis-derived regions from both attention shifting and working memory are defined electronically and may be used as regions of interest in future studies.

Arousal↗

PubMed1994

A meta-analysis of two different trials on posterior resin-bonded bridges.

In a meta-analysis the results of two different trials on posterior resin-bonded bridges (PRBBs) were combined. The common experimental variable 'preparation form' and the variable 'location' were combined for this analysis. The meta-analysis showed a highly significant effect for the variable 'location' (P < 0.001). Although the experimental variable 'preparation form' had no significant influence in the separate trials, the combined study revealed a significant effect for this variable on the retention of PRBBs (P = 0.03).

Clinical Trials as Topic↗

PubMed2000

Distribution of the standardized mean change effect size for meta-analysis on repeated measures.

When conducting a meta-analysis on studies with repeated measures, a useful measure of effect size is Becker's (1988) standardized mean change. This paper examines the distributional properties of the standardized mean change, and discusses potential problems with the variance formulae given in Becker (1988). First, an error in the exact variance formula can lead to severe underestimation of the actual sampling variance. Second, Becker (1988) recommended the use of an approximation which is shown to underestimate the sampling variance when sample size is small. Using the approximation can decrease the accuracy of meta-analysis results; however, the degree of error is generally small.

Humans↗

PubMed2026

Photon-counting detector computed tomography (PCD-CT) in multiple myeloma: a systematic review and trial sequential meta-analysis on image quality and radiation dose.

OBJECTIVES: To systematically review and perform a meta-analysis comparing the effects of PCD-CT versus EID-CT on image quality (sharpness) and radiation dose (CTDIvol) in patients with bone lesions due to multiple myeloma (MM). METHODS: A comprehensive search of PubMed, Embase, Scopus, and Cochrane Central was conducted from inception to October 2025. Studies comparing PCD-CT and EID-CT in MM patients were included. Methodological quality was assessed using ROBINS-I, and the certainty of evidence was assessed using GRADE. RESULTS: A total of 41 studies were identified that matched our search criteria. After duplicate removal and screening, five studies (n = 170 patients) were included in the systematic review, with four contributing to the meta-analysis. PCD-CT showed a significant pooled mean difference in image sharpness (mean difference, + 0.99 points; 95% CI, 0.62-1.37; p < 0.001). PCD-CT also demonstrated a reduction in radiation dose (mean difference, -4.95 milligrays; 95% CI, -8.39 to -1.50; p = 0.005). Trial sequential analysis (TSA) confirmed stability of pooled estimates, with conclusive evidence for image sharpness improvement, and suggestive yet incomplete evidence for radiation dose reduction. CONCLUSION: Compared to EID-CT in MM, PCD-CT significantly improves subjective image sharpness as supported by trial sequential analysis. Conventional meta-analysis suggested a reduction in radiation dose with PCD-CT; however, trial sequential analysis indicated that the cumulative evidence remains inconclusive. Further large-scale studies are suggested to confirm the magnitude of the radiation dose reduction benefit.

Humans↗

PubMed2003

Allogeneic blood transfusion increases the risk of postoperative bacterial infection: a meta-analysis.

BACKGROUND: Immunosuppression is a consequence of allogeneic (homologous) blood transfusion (ABT) in humans and is associated with an increased risk in cancer recurrence rates after potentially curative surgery as well as an increase in the frequency of postoperative bacterial infections. Although a meta-analysis has been reported demonstrating the relationship between ABT and colon cancer recurrence, no meta-analysis has been reported demonstrating the relationship of ABT to postoperative bacterial infection. METHODS: Twenty peer-reviewed articles published from 1986 to 2000 were included in a meta-analysis. Criteria for inclusion included a clearly defined control group (nontransfused) compared with a treated (transfused) group and statistical analysis of accumulated data that included stepwise multivariate logistic regression analysis. In addition, a subgroup of publications that included only the traumatically injured patient was included in a separate meta-analysis. A fixed effects analysis was conducted with odds ratios obtained by using the conditional maximum likelihood method and 95% confidence intervals on the obtained odds ratios were determined using the mid-p technique. RESULTS: The total number of subjects included in this meta-analysis was 13,152 (5,215 in the transfused group and 7,937 in the nontransfused group). The common odds ratio for all articles included in this meta-analysis evaluating the association of ABT to the incidence of postoperative bacterial infection was 3.45 (range, 1.43-15.15), with 17 of the 20 studies demonstrating a value of p < or = 0.05. These results provide overwhelming evidence that ABT is associated with a significantly increased risk of postoperative bacterial infection in the surgical patient. The common odds ratio of the subgroup of trauma patients was 5.263 (range, 5.03-5.43), with all studies showing a value of p < 0.05 (0.005-0.0001). These results demonstrate that ABT is associated with a greater risk of postoperative bacterial infection in the trauma patient when compared with those patients receiving ABT during or after elective surgery. CONCLUSION: These results demonstrate that ABT is an associated and apparently significant and frequently overlooked risk factor for the development of postoperative bacterial infection in the surgical patient. Allogeneic blood transfusion is a greater risk factor in the traumatically injured patient when compared with the elective surgical patient for the development of postoperative bacterial infection.

Bacterial Infections↗

PubMed2004

Meta-analysis of association between the T102C polymorphism of the 5HT2a receptor gene and schizophrenia.

A meta-analysis of whole-genome linkage scans confirmed linkage between schizophrenia and markers on the long arm of chromosome 13. The gene HTR2A, which codes for the 5HT2a receptor, is located in this area. The T102C single nucleotide polymorphism of HTR2A has been the subject of much research. The production of the C-allele form of HTR2A is significantly less than that of the T-allele form in normal controls and schizophrenic patients. Although the association of schizophrenia with the C allele of HTR2A was confirmed by a meta-analysis 5 years ago, there was a continuous debate because negative findings were also considerable, which may have been due to ethnic differences in association. We performed another meta-analysis, since the number of available studies of this association has recently doubled. In the meta-analysis of 31 case-control association studies, we found a significant association between the C allele of the T102C polymorphism and schizophrenia, which was more pronounced in European samples than in the entire sample. We found significant heterogeneity in the allele-wise analysis (C vs. T) and homozygous genotype-wise analysis (CC vs. TT), both of which were at least partially explained by differences between samples from Asian and European countries. In East Asian countries, there was not a significant association with the C allele or CC homozygosity, indicating strong genetic differences and noncombinability of data between European and East Asian populations. Interestingly, the frequency of the T allele was much higher in East Asian patients and controls (59.5% and 57.5%, respectively) than in European patients and controls (40% and 43.5%, respectively). In five family-based association studies, we did not find significant evidence for association of the C allele with schizophrenia; yet, the pooled OR was 1.3 (95% CI=0.9-1.8, z=1.47, p=0.14), which is consistent with the results of the case-control studies. The effects of other genes, environmental effects on DNA methylation, or different methods of classification may be the causes for such heterogeneity, but more study in this area is needed.

Gene Expression↗

PubMed1998

Meta-analysis of streptokinase and heparin in deep vein thrombosis.

The efficacy and safety of streptokinase and heparin in deep vein thrombosis (DVT) were compared in a meta-analysis. Randomized trials in which streptokinase (followed by heparin) and heparin alone were compared in treating phlebographically documented acute DVT were identified from MEDLINE and other sources for a meta-analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) based on the logit method were computed for each study. A fixed-effect model was used to combine the study results, enabling differences between streptokinase recipients and recipients of heparin alone to be expressed as summary ORs with 95% CIs. Significantly more streptokinase recipients achieved thrombolysis than recipients of heparin alone (summary OR, 6.24; 95% CI, 3.62 to 10.78). One study was identified as an outlier and excluded from the analysis. The meta-analysis then showed that streptokinase recipients were significantly less likely to have postthrombotic changes (summary OR, 0.40; 95% CI, 0.18 to 0.88) and postphlebitic changes (summary OR, 0.32; 95% CI, 0.12 to 0.86) in phlebographic evaluation. The frequency of major bleeding was significantly higher among streptokinase recipients than recipients of heparin alone (summary OR, 3.78; 95% CI, 1.26 to 11.32). A meta-analysis showed that, compared with heparin alone, streptokinase therapy for DVT was associated with significantly more frequent thrombolysis and major bleeding; after exclusion of one outlying study, analysis showed that streptokinase therapy was associated less frequently than heparin alone with postthrombotic changes (assessed by phlebographic evaluation) and postphlebitic syndrome.

Fibrinolytic Agents↗

PubMed2006

Reduction in the risk of developing back pain persists at least 30 months after discontinuation of teriparatide treatment: a meta-analysis.

INTRODUCTION: Teriparatide [rhPTH (1-34)] reduces fracture risk, and in a published meta-analysis of clinical trials, teriparatide-treated patients had reduced incidence of back pain relative to placebo or to antiresorptive drugs. The aim of this study was to evaluate back pain in teriparatide-treated versus comparator-treated patients during an interval including controlled clinical trials plus 30 months of additional follow-up. METHODS: A meta-analysis of four completed randomized, double-blinded trials of teriparatide [rhPTH (1-34)] versus comparator was performed. A multivariate Cox proportional hazards model was used to assess the heterogeneity of results and to estimate the relative risk of back pain. RESULTS: Patients in the pooled teriparatide group had reduced risk for any back pain [relative risk, 0.73 (95% CI, 0.61-0.87)], moderate or severe back pain [0.72 (0.58-0.89)], and severe back pain [0.39 (0.25-0.61)] compared with pooled controls, from initiation of the study drug through the end of follow-up. Sensitivity analysis showed that the results were robust to the removal of each individual trial from the meta-analysis. Separate meta-analyses comparing teriparatide versus placebo or antiresorptive drugs gave similar results. CONCLUSIONS: Teriparatide-treated patients had a reduced incidence of back pain versus those receiving a comparator during an observation encompassing clinical trials plus 30 months of posttreatment observation.

Back Pain↗